The claimant must show that the defendant caused them a loss. The Courts have had to define the test for causation, which is split into factual and legal causation, and then determine the meaning of ‘loss’.
The first case summaries involve questions of factual causation, which usually requires an application of the ‘but-for’ test. Where there has been issues of evidence and proof, the Courts have applied a different test looking at the contribution to the risk of damage or harm.
The next set of summaries look at the test for legal causation, as in proving the defendant in law caused the loss. The Courts have to decide whether an intervening event has broken the chain of causation, such that the defendant is no longer responsible for the claimant’s loss.
The final cases concern the meaning of ‘loss’.
1 – Factual Causation
The Courts usually apply the ‘but-for’ test to determine whether the act of the defendant factually ‘caused’ the claimant’s loss. If the loss would not have occurred ‘but-for’ the defendant’s actions, the Courts will say as a matter of fact that the defendant caused the loss.
Barnett v Chelsea and Kensington Hospital Management Committee 
Barnett demonstrates that the defendant must cause the loss, and it is for the claimant to show this. In Barnett, the claim was dismissed because, even though the doctor was negligent, on the balance of probability the doctor’s failure to take reasonable care had not caused the defendant’s death.
For successive tortious events, the second defendant is only liable for any extra damage they cause.
Performance Cars Ltd v Abraham 
Performance Cars Ltd v Abraham raised a novel point concerning successive events. Where two events cause the same harm which requires the same cost of repair, the second defendant can not be said to have caused this loss. The second defendant is only liable for any extra damage caused.
The House of Lords approved the decision in Performance Cars Ltd v Abraham. Where two persons do successive, separate acts causing the same loss, the second person is not liable for that loss. The second defendant will only be liable for any extra damage caused. Jobling v Associated Dairies 
In Jobling v Associated Dairies, the House of Lords reaffirmed the ‘vicissitudes’ principle to reduced the damages award where a second, natural event which would have occurred anyway overtook the claimant’s initial injury.
Exceptions to the but-for test
In some cases, particularly where there is insufficient evidence to determine what was the cause of an injury, the Courts have adopted a lower standard of test for factual causation.
Wardlaw v Bonnington Castings Ltd 
In Bonnington Castings, the House of Lords held the defendant was liable to the full extent for the claimant’s harm where their negligence was one of a number of sources of the damage but materially contributed to the injury.
In Holtby, the Court of Appeal concluded, following Bonnington Castings, that the defendant did factually cause the damage because they materially contributed to it. However, unlike in Bonnington Castings only held the defendant liable to the extent of their contribution. McGhee v National Coal Board 
In Holtby, the Court of Appeal concluded, following Bonnington Castings, that the defendant did factually cause the damage because they materially contributed to it. However, unlike in Bonnington Castings only held the defendant liable to the extent of their contribution. Fairchild v Glenhaven Funeral Services 
The House of Lords approved the judgement in McGhee v National Coal Board in Fairchild v Glenhaven Funeral Services, affirming that in certain cases it is sufficient for the claimant to show the defendant materially contributed to the risk of harm. This principle was extended in Fairchild to include cases where a claimant can show that multiple claimants contributed to their harm, although can’t show with certainty which defendant was the but-for cause of the harm.